Optical transceivers are electro-optic devices that generally convert optical signals from a fiber optic cable into electrical signals, and vice versa. Optical transceivers are typically used as an interface between a fiber optic cable and a communication device, such as a communications node in a network and as such is usually mounted (i.e., attached) to a printed circuit board of a communication device as well as a fiber optic cable.
The way in which transceivers are attached to a printed circuit board is usually controlled by an industry standard. Industry standards ensure that each manufacturer of a transceiver meets certain criteria to ensure consistency for designs of printed circuit boards configured to receive the transceiver and interchangeability of transceivers among different manufacturers of transceivers. For instance, industry standards typically govern the size of a transceiver, packaging (if any) for retaining the transceiver, and its input and output (I/O) pin configurations including: the number of pins, spatial relation of each pin, electrical signal assignments for each pin, and so forth. Each industry standard inherently controls how to interface (i.e., to connect) the transceiver to a printed circuit board. For example, holes of a receptacle located on the printed circuit board for receiving pins of a transceiver or transceiver housing, must be complementary and align with the pins of the transceiver or transceiver housing. Additionally, the receptacle holes must align electrically with the signal assignments of the pins of a transceiver or transceiver housing.
Most transceivers are either manufactured in accordance with one of two industry standards: the Small Form Factor (SFF) or Small Form Factor Pluggable (SFP). Transceivers manufactured in accordance with the SFF industry standard (“SFF transceivers”) are typically electrically and mechanically mounted directly to a printed circuit board. That is, the leads or pins of the SFF transceiver are soldered directly to a printed circuit board. The pins of the SFF transceiver are soldered to holes of a complimentary receptacle on the printed circuit. The holes of the printed circuit board are typically connected to conductive traces contained within the printed circuit board.
Increasingly, transceivers are being manufactured in accordance with the SFP standard (“SFP transceivers”). SFP transceivers have an advantage over SFF transceivers, as the SFP transceiver slides inside a housing and plugs into a connector located in the housing without the need for soldering or pin alignment. Accordingly, the SFP transceiver can be field replaced simply by pulling the SFP transceiver out of the housing and plugging in a replacement SFP transceiver. The housing and connector are mated to the printed circuit board, by mechanical and electrical mechanisms. Accordingly, when updates or improvements are made to a transceiver design, it can be installed onto the printed circuit board simply by pulling an older version of the SFP transceiver out of the SFP housing and inserting the updated version therein.
Unfortunately, customers that have printed circuit boards designed to connect with SFF transceivers cannot take advantage of the newer SFP transceivers, because the SFF and SFP transceiver footprints are not compatible with one another. That is, the housing and connector of an SFP transceiver has pins and fastening mechanisms that are not aligned with the holes of a receptacle configured to accept an SFF transceiver. Accordingly, replacing the SFF transceiver with an SFP transceiver is not possible, because even if the SFF transceiver is removed from the board, the SFP transceiver housing's footprint, and electrical pin assignment is incompatible with a receptacle on a printed circuit board configured to receive a SFF transceiver.
One possible solution to this problem involves redesigning the artwork of the printed circuit board and replacing the old SFF compliant printed circuit boards in their entirety. However, to design such a printed circuit board and replace the older ones is time consuming, expensive and inconvenient. This is especially problematic if there are multiple product lines each having different printed circuit board designs and sizes, as each must be customarily redesigned to include an SFP transceiver.